1. Field
The present invention relates generally to a locking device, and more particularly to a locking device which can secure a heat sink to a heat generating device mounted on different PCBs with different layouts.
2. Prior Art
It is widely acknowledged that heat is produced during operation of electronic devices such as central processing units (CPUs). The heat produced must be quickly removed to ensure the CPUs working normally. Typically, a heat sink is provided to remove heat from the CPU. In order to keep the heat sink intimately contacting with the CPU, a locking device is generally required.
For instance, FIG. 7 illustrates a conventional locking device used for securing a heat sink to a CPU 1 mounted on a printed circuit board (PCB) 2. The locking device comprises a planar locking plate 3 and a plurality of screws 4. The heat sink comprises a radial fin section 7 and a heat-conducting pillar 5 having an upright column 6. A plurality of retaining members 9 each with a retaining hole, i.e. threaded hole defined therein, is provided at the PCB 2 surrounding the CPU 1. The locking plate 3 at corners thereof defines a plurality of through holes 8 in alignment with the threaded holes of the retaining members 9. In assembly, the fin section 7 is attached to the column 6 after the column 6 extends through and projects beyond the locking plate 3. The screws 4 extend through the through holes 8 of the locking plate 3 and further engage with the PCB 2 in the threaded holes of the retaining members 9 respectively, to cause the locking plate 3 to press the pillar 5 downwardly against the CPU 1. Thus, the heat sink is secured to the CPU 1 for heat dissipation. However, the above-mentioned locking device is only applicable for securing the heat sink to the PCB with the retaining members 9 completely in alignment with the through holes 8 of the locking plate 3. Instead, when the PCB having retaining members 9 different from the above-mentioned layout is used, it is impossible for the above-mentioned locking device to do such a securing job.